Spitzer Space Telescope - General Observer Proposal #12043
Search for CO2/CO Band Emission in Active Asteroid 324P
Principal Investigator: Michael Mommert
Institution: Northern Arizona University
Technical Contact: Michael Mommert, Northern Arizona University
Co-Investigators:
Joseph L. Hora, Harvard-Smithsonian Center for Astrophysics
Henry H. Hsieh, Institute of Astronomy and Astrophysics, Academia
David E. Trilling, Northern Arizona University
Scott S. Sheppard, Carnegie Institution for Science
Science Category: asteroids
Observing Modes: IRAC Post-Cryo Mapping
Hours Approved: 5.1
Priority: 1
Abstract:
Until a few decades ago, the distinction between asteroids and comets seemed to
be simple: comets exhibit activity in the form of a coma and/or a tail as a
result of the sublimation of surface ices, whereas asteroids are inactive, rocky
bodies. The separation between the two groups became less clear with the
discovery of asteroidal bodies that exhibit comet-like dust activity - the
active asteroids. For some of those objects, disruption or mass loss due to
rotational destabilization or recent collisions are the most likely processes
causing the activity. Other objects display recurrent dust activity near
perihelion that seems to be caused by the sublimation of ices, but gases have
never been directly measured in them. We propose the first Spitzer observations
of recurrently active asteroid 324P to search for emission from CO2 or CO. Our
observations will detect emission from either gas with unprecedented sensitivity
and provide the first ever confirmed detection of volatiles in an active
asteroid. We will measure the CO2/CO gas production rates - or put upper-limits
on them in the case of a lack of emission. The detection of sublimation-driven
activity in active asteroids provide important constraints on the volatile
inventory of the inner Solar System and Solar System formation models, gives
insight into volatile preservation/retention in asteroidal bodies, and may be
relevant to primordial terrestrial water delivery scenarios, as well as future
asteroid resource utilization. This proposal conforms with the Spitzer Cycle 12
focus on planetary science programs observing targets in our Solar System.